Lamp support arm



FIG. 1 is a side elevational view of the lamp support arm in accordance with my design, illustrated in an environment of a lamp;

FIG. 2 ia a top plan view of the lamp support arm in accordance with my design;

FIG. 3 is a front elevational view of the lamp support arm in accordance with my design;

FIG. 4 is a left side elecational view of the lamp support arm in accordance with my design, the right side being a mirror image thereof;

FIG. 5 is a rear side elevational view of the lamp support arm in accordance with my design; and,

FIG. 6 is a bottom plan view of the lamp support arm in accordance with my design.

The broken lines show the environment in which the article is used and are not considered part of the design claimed. 

The ornamental design for the lamp support arm, as shown and described. 